哈工大信息光学Chapter3-1.pdf

幻 灯 片 Chapter 3 1 Foundations of Scalar Diffraction Theory Weimin Sun College of Science Harbin Engineering University 幻 Diverge ：脱离，分叉 灯 The Rayleigh-Sommerfeld 片 Diffraction Formula 2 The equation below expresses U(P ) 0 the observed field U(P ) as a r01 0 superposition of diverging U(P ) 1 q spherical waves exp(jkr 01)/r01 originating from secondary sources located at each and every point P1 within the aperture . 1 exp(jkr 01 ) U(P ) U (P ) cos(q)ds 0 1 j l r 01 幻 Directivity: 指向性 灯 Property of the secondary Pattern ：模式，图案 片 source at P 1 3 1 exp(jkr 01 ) U(P ) U (P ) cos(q)ds 0 1 j l r 01 n It has a complex amplitude that is proportional to the amplitude of the excitation U(P ) at the 1 corresponding point. n It has an amplitu